Disclosed herein is a method and system for creating gloss images using differential gloss, as well as the corresponding computer-readable medium.
Gloss is an image or substrate attribute that describes how much specular reflection one get from a surface of a substrate. Specular reflection is the mirror-like reflection of light from a surface, in which light from a single incoming direction is reflected into a single outgoing direction. Because the surface of the substrate is not always perfectly flat, the light reflected from the surface of the substrate is not similar to what would generally be reflected from a mirror. When a surface of a substrate is rough, the percentage of the light that is reflected as specular reflection is less. In general, the rougher the surface, the lesser the chance of the reflected light is going to travel in the direction of the specular reflection. By varying the roughness of the surface, different types of finishes may be achieved.
One current technology that may be used to generate image-wise gloss effect is referred to as glossmark. Glossmark may involve paper, ink, halftones, and the manner of fusing the ink onto the paper. By adjusting the combination, the gloss can be modulated, creating a subtle image that may be viewed when the paper is held a certain way. The glossmark technology is described in US Patent Publication No. 20040001233 titled “Protecting printed items intended for public exchange with glossmarks” and US Patent Publication No. US20040156078 titled “Application of glossmarks for graphics enhancement”. One disadvantage of the glossmark technology is that it can only be created at limited colors with small contrast. Another current technology that may affect a roughness of a surface is laser engraving. Laser engraving is the practice of engraving or marking an object by removing the materials from a solid surface using a high power laser. One of the disadvantages of laser engraving is that it requires very high energy: power density and energy density. Because of the high energy required, the speed of laser engraving is slow. Further, laser engraving generates fume and dust which is not environmental and user friendly. In addition, image resolution of laser engraving is very limited.